Control device



A. DESFACHELLES CONTROL DEVICE Filed Nov. 25, 1938 Dec. 10, 1940.

10 I Inventor: 6 Alexandre Desfachel les,

Patented Dec. 10, 1940 UNITED STATES PATENT OFFICE CONTROL DEVICEporation oi New York Application November 25, 1938, Serial No. 242,404In France November 30, 1937 6 Claims.

This invention relates to control devices, more particularly to controldevices for heating apparatus, such as the hot-plates of an electricrange, and it has for its object an improved device of this character.

It has been already proposed to supply electric resistance-type heatingapparatus intermittently and to efiect the regulation of the heating byvarying the relative duration of the successive periods during which theheating resistances are supplied and during which no power supplyreaches the resistances. This methed of regulation amounts to varyingthe average power which is supplied to the heating resistances, and itprovides for a gradual variation in the mean power from a minimum valuewhich may be equal to zero up to a maximum value corresponding to thepermanent power supply.

In apparatus which are provided with notchtype means of regulating therate of heating, for instance in apparatus whose heating resistance issubdivided into several sections which may be coupled in series or inparallel, or which may be utilized separately, the regulation accordingto intermittent supply, whose principle has just been recorded, may besuperimposed on the notching regulation, so as to permit a progressiveregulation starting from each or from some of the heating levels,corresponding to the notch regulation. The combinations of this typewhich have been known so far comprise two handles or other similar partsfor controlling the regulation, which are quite distinct one from theother; one of these controlling handles regulates the notches, while theother takes care of the gradual regulation.

Such an arrangement has shortcomings, especially in electric apparatusfor cooking purposes, such as heating plates, ovens, kitchen ranges,etc., whose utilization is complicated by that arrangement, since itentails groping and is likely to bring about false maneuvers.

The present invention avoids these shortcomings. the regulation ofelectric kitchen appliances involving electric heating. However, it canbe generally applied to all electric heating apparatus which comprises asuperimposition or a combination of a regulation by notches and ofprogressive regulation according to the intermittent method; for thatapplication simplifies the control of the heating apparatus byincreasing the reliability of the maneuvers while at the same time itreduces the size of the regulating devices.

This invention is especially directed to In a copending application ofWallace J. Ettinger and Russell A. Winborne, Serial No. 337,758, filedMay 7, 1940, there are described and claimed features which areincorporated in the control device of the present application in whichswitch means are provided to energize one heating resistance or morethan one to provide different degrees of heat, and furthermore, acontrol element is provided to control the average power supplied to theone resistance when it is energized. A single control member controlsthe operation of the switch means and the control element so that whenthe control member is operated through one range of movement the oneresistance only is energized, and the average power supplied to it iscontrolled, and when in another position, the plurality of resistancesare energized to effect a constant degree of heat; in this latterposition of the control member, the control element is renderedinefiective to control the average power supplied.

In accordance with this invention, a master switch is provided forestablishing the heating connections so that either one or more than oneresistance may be energized to provide difierent degrees of heat, and asecond switch is provided for controlling the average power supplied tothe one resistance when it is energized. A regulator controls the secondswitch to control the average power supplied. This regulator and themaster switch are under the control of a single control member.

For a more complete understanding of this invention, reference should behad to the accompanying drawing in which Fig. 1 is a side elevation of acontrol device arranged in accordance with this invention; Fig. 2 is aview taken along the lines 2-2 of Fig. l and looking in the direction ofthe arrows; Fig. 3 is an elevation illustrating certain elements of thecontrol device and occupying positions corresponding to the position ofthe control knob shown in Fig. 2; Figs. 4 and 5 are similar to Figs. 2and 3 respectively, but illustrate certain elements in differentoperative positions; Figs. 6 and '7 are similar to Figs. 2 and 3respectively but illustrating certain parts in still other operativepositions; and Fig. 8 is a diagrammatic representation of certain of theelements of the control device of Fig. 1 and also of certain heatingresistance elements controlled by the control device.

The attached schematic drawing represents a physical embodiment given byway of a non-limiting example of the invention. This example is assumed,in order to facilitate the description, to

refer to the regulation oi a heating plate cooking purposes, comprisinga resistance which is divided into two sections A and B: section A mayfor example producedzoo watts, while resistance B may produce 600 watts.It has been besides assumed that the notch-type regulation is tocomprise three levels; all power supply is cut oil; that is the zeroposition (no power): a section of resistance A alone is supplied (power=1200 watts); sections A and B are supplied in parallel (power=1800watts); the progressive regulation is assumed to cover the. whole rangefrom zero to 1200 watts. t

The single control element is here shown as a handle I, which actuates ashaft 2 on which is keyed a rotating drum 3 that carries the movablecontacts 2a, 3b and 2c of the change-over switch that brings about thenotch-type regulation. This change-over switch is here assumed to be ofthe drum type and its movable contacts make, depending upon the positionof handle I, the necessary variable connections between the fixedcontacts 4, 5 and is that are connected to; the supply line 6, as shown,and the fixed contacts I, 8 and 9 that are connected respectively to thecommon point ill of the sections A and B 01' the heating resistance andto the i'reeends of these sections. 7

The supply according to the intermittent method is assumed to beobtained by means oiv a mercury tilting orrocking switch ll, insertedbetween I and I; this rocking switch is carried by a cradle I2 whichoscillates about the fixed shaft i3 and is held by a spring i4 in theclosing position; that is to say, the horizontal position. Thebimetallic strip II which becomes deformed under the influence oi theheat which it receives from a heatingelement It when the latter isenergized, pushes, when a certaintemperature is reached, (correspondingto a given supply time of that heating element) the extremity-providedwith a regulating screw I oi a lever it carried by the oscillatingcradle i2 on which is mounted the rocker; in this manner the bimetallicstrip II introduces the power supply to the heating resistance by causing the rocker to oscillate in the direction of arrow is against theeifect oi spring l4. The bimetallic strip I! together with the heatingelement ii are mounted on a shaft 20, and a spring 2| tends to rotatethis system in the direction of arrow 22 (Fig. 3). A cam wheel 23, whichis actuated by the shait 2, permits removing (against the spring 2|) thesystem ll6 from the extremity ll of the oscillating Y lever II, orpermits bringing it closer to that extremity ii, consequently toincrease or decrease the duration of the supply periods for the heatingresistance (progressive regulation of the heating). The mechanism formarking the notches comprises a-cam wheel 24 which is actuated by theshaft 2 and with which cooperates a roller 25 which is held against camwheel 24 by a lever 26 articulated on a fixed shat-t 21 which is underthe influence of a tension spring 28.

The operation is as follows: We start from the position oi Figs. 1, 2, 3and 8, where all supply is interrupted, cam wheel 24 being keyed onshaft 2 in such a. way that the roller is engaged by one of its notches,and cam 23 being keyed in such a way that the tree extremity of thebimetallic strip l5 comes nearly in contact with the extremity ll of theoscillating lever It. By causing the handle I to rotate in the aaaesosfor direction of arrow 20.

to... position or m. 2 to Fig.4, the section of resistance Ais direc lysupplied by a circuit which may be'traced from,

thesupplvconductorl tbroughtheclosed switch contact-I, the switch II,the resistance A. the closed contact 2 and thence to the opposite supplyconductor 5. The heating element II is supplied at the same time inseries with the section oi resistance B and the rocker ii through acircuit which may be traced from the supply conductor 4; the closedcontact I, the switch Ii and thence through the resistance B and theheating element It in series to the opposite supply conductor 6. Becauseof the magnitude of the resistance of It with respect to that of B.nearly the entire heat produced is emitted in i6, and, inasmuch as theenergy expended in B is negligible, everything is as it the section Bhad remainder unutilized; the rocker II is actuated (the circuit of theheating element 18 being interrupted at the same time as that of A), andthe section or resistance A is supplied according to the intermittentmethod. At the beginning oi the rotation oi handle i, the tree extremityof the bimetallic strip I! being initially very close to II, theduration 01' the supply periods for A is very short and the power verylow. By turning the handle i gradually in the direction of the arrow 29(Fig. 2) the duration of the supply periods for A and consequently itsheating capacity is gradually increased. This operation of the handle,as will be understood, moves the thermostat away irom the screw ll.

During this entire part of the rotation of handle I, the roller 25 restson the circular part of theprofile oi cam wheel 24 and the spring 20applies a sumcient pressure so that this handle I rests in any positionin which it is left;

When one reaches the extremity of the circular part oi the profile ofcam 24, the cam wheel 23 has removed the system Iii-l6 from H to asuflicient distance so that the supply of A becomes permanent:capacity=l200 watts. By continuing to rotate the handle I in thedirection of arrow 29, the cam wheel 24 reaches the position shown inFig. 6, and the sections of resistances A and B are supplied.simultaneously and permanently in parallel, the heating element It beingshorted out by closing contact 8 which operation also maintains theconnection through the resistance B.

By continuing the rotation of handle I in the direction of arrow 20,11;is returned to the "on" position shown in Fig. 8, and by rotatinghandle.

I in the opposite sense, one would obtain, in the reverse'order, thesame regulations.

While I have shown a particular embodiment of my invention, it will beunderstood, of course, that I do not wish to be limited thereto sincemany modifications may be made, and I, therefore, contemplate by theappended claims to cover any such modiflactions as fall within the truespirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A control device for an electric hotplate having a pair of heatingresistances comprising switching means operable to selected controllingpositions to connect said resistances to a supply source to provide aplurality of diilerent heats, a control member operating said switchingmeans to said controlling positions so that when said control member ismoved in one direction from an oil position it connects one of saidresistances to the full voltage 01- said supply source to provide oneheat, a thermally responsive switch operable to control the connectionsto said one resistance to regulate the average power supply to it andcontrolled by said control member to increase graduallythe power inputto said one resistance to provide higher and higher heats as saidcontrol member is advanced in saidone mally responsive switchineiTective to regulate 'average power so that one resistance providesconstant heat and upon still further movement in said one directionconnecting said two resistances to thefull voltage of said supply sourceto provide a still higher constant heat for said hotplate.

2. In a heating system having a pair of heating resistances and anelectrical supply source for the resistances, a switch arranged in oneposition to connect at least one of said resistances to the supplysource so that the full voltage of the supply source is impressed onsaid resistance, and in another position the two resistances areconnected in parallel with the full voltage of the supply sourceimpressed on them, a control knob for operating said switch to saidpositions, a second switch controlling said one resistance, a thermostatcontrolling the operation of said second switch intermittently tocontrol the average power supplied to said one resistance, an auxiliaryheater for heating said thermostat intermittently controlled by thethermostat to cut off heat from said thermostat when power is removedfrom said one resist-ance and to reapply heat to said thermostat whenpower is reapplied to said one resistance, means operated by saidcontrol knob for adjusting said thermostat to vary the power input tosaid one resistance, and means operated by said control knob for turning01! said auxiliary heater and rendering said thermostat ineffective whensaid first switch is moved to its position to connect both of saidresistances to said supply source.

3. In a heating system having a pair of heat ing resistances and anelectrical supply source for the resistances, a control device for saidresistances comprising a shaft, a switch operated by said shaft toconnect one of said resistances to the supply source so that the fullvoltage of the source is impressed on it in one position of the shaft,and to connect the two resistances to the source to impress its fullvoltage on them in another position of the shaft, a thermostaticallyoperated switch connected in the circuit of said one resistanceoperating to regulate the power supplied to the resistance, saidthermostatically operated switch having a bimetallic operating bar and aheater for applying heat to the bar to move it to operate the switch toout said one resistance from the supply source, said heater controlledby said bar to remove heat from the bar at the same time said oneresistance is cut from the supply source so that the bar cools toreconnect said one resistance to said source and said heater controlledby the bar to restore heat to the bar at the same time said oneresistance is reconnected to said source, a cam operated by said shaftwhen moving between said two positions to control the position of saidbimetallic bar so as to vary the power supplied to said one resistanceand functioning to render the thermostatic bar inoperative when theshaft is moved to said other position when both of said resistances areconnected to said supply source, and

positioning means for locating said shaft in said two positions.

4. In a heating system having a pair of heating resistances and anelectrical supply source for the resistances, a control device for saidresistances comprising a shaft, a switch operated by said shaft toconnect one of said resistances to the supply source so that the fullvoltage of the source is impressed on it in one position of the shaft,and to connect the two resistances the source to impress its fullvoltage on iem in another position of the shaft, a licnid contact switchconnected in the circuit of said one resistance to make and break saidcircuit depending on the position of said switch, leans movably mountingsaid switch. an operating member for said switch, a thermostatcontrolling said operating member to vary the position of said switch, aheater for heating said thermostat intermittently controlled by thethermostat to cut heat from it when the thermostat moves said liquidcontact switch to cut oil power from said one resistance and to reapplyheat to the thermostat when it operates to move the switch to reapplypower to said one resistance, and means operated by said shaft forvarying the relation of said thermostat to said operating member to varythe operation of said liquid contact switch by said thermostat so thatvarying degrees of power are supplied to said one resistance atdifferent positions of said shaft.

5. In a heating system having a pair of heating resistances and anelectrical supply source for said resistances, means for controllingsaid resistances comprising a thermostatically operated timing switchand a master switch. the latter operating through said thermostaticallyoperated switch in a series of positions to connect one only of saidresistances to said supply source and in another position to connectboth of said resistances to said supply source, said thermostaticallyoperated switch being rendered ineffective to govern the power supply tosaid resistances when said master switch is in said other position andrendered effective to control the average power supplied to said oneresistance when said master switch is in any one of said series ofpositions and supply different average powers to said one resistance foreach of said series of positions.

6, In a heating system having a pair of heating resistances and anelectrical supply source for said resistances, control means for saidsystem comprising a switch adapted to be connected in the connectionsbetween said supply source and said resistances, a thermostat foroperating said switch, an auxiliary heater for applying heat to saidthermostat, a master switch adapted to control said connections arrangedin one position to connect both of said resistances to said supplysource while said auxiliary heater remains unenergized so that the tworesistances supply a, constant high heat, and in a series of otherpositions to connect one of said resistances together with saidauxiliary heater to said supply source and to control the operation ofsaid thermostatically operated switch so that said switch operates tocontrol the average power supply to said one resistance, the averagepower supply depending upon the position of said master switch wherebysaid one resistance generates different degrees of heat depending uponthe position of said master switch.

ALEXANDRE DESFACHELLES.

DISCLAIMER .2,224,596.-Almndre Deajachellu, A Ronchin, 'N ra, Fm. mm].Dmct.

Patent dated December 1940. D-iaclmmer filed June 23, 1943, by theassignee, General Company. e Y Hereby disclhims claim 5.

[Qfiicial Gazette July 18, 1943.]

,2,224,596.Almndre Deafachella, A Ronchin, Nora, France. gum-1. Dzvzc'x.

DI sc LAI M E'R' Patent dated December 10, 1940. Disclaimer filed June23, 1943, by the assignee, General Electric Company.

Hereby disclhims claim 5.

[Oflicial Gazelte July 13; 1948.]

